Double twist twisting apparatus and method



July 9, 1968 A. WAHLEN 2 DOUBLE TWIST TWISTING APPARATUS AND METHOD Filed Dec. 6, 1966 ii F .1 I

INVEN 71-1 ANTONIUS WAHLEN ATTYS I United States Patent Office 3,391,529 DOUBLE TWIST IWISTING APPARATUS AND METHQD Antonius Wahien, Remscheid-Lennep, Germany, assignor to Barmag Barmer Maschinenfabrik Aktiengesellschaft, Wuppertal, Germany Filed Dec. 6, 1966, Ser. No. 599,439 Ciaims priority, application Germany, Dec. 13, 1965, B 84,948 7 Claims. (Cl. 5758.83)

ABSTRACT OF THE DESCLOSURE Double twist twisting apparatus and method using a thread balloon support ring concentric with and rotating with the spindle to prevent collapse of balloon of fine denier threads at the critical balloon contraction zone.

Background of the invention As is well known, when twisting threads on double twist twisting devices, the thread exits radially out of the spindle core and winds first of all around a respectively more or less large portion of the circumference of the reserve disc before running over a run-over body constructed in disc-like or dish-like fashion and rotating together with the spindle. The thread orbits in a thread balloon as it travels to the thread guide coaxially positioned above the spindle. It is drawn through the spindle and guide by a draw-E installation or take-up installation. See U.S. Patents Nos. 1,900,037 and 2,867,968 and British Patent No. 961,853. It is known in such twisting devices to employ so-called balloon limiting devices which are set up concentrically around the spindle as stationary or likewise revolving wide rings or cup-shaped structures and which serve for the narrowing down of the balloon or of its diameter from the outside in order to reduce the thread tension, or to define the individual twisting spot more closely. See U.S. Patent No. 3,077,726 and British Patent No. 989,235. Also, it is known to employ a stationary protective casing concentrically about and completely concealing the feed spool, which protective casing serves to limit or define the inner thread balloon path during the start of the twisting and around which casing the thread balloon (possibly likewise limited on the outside by a stationary casing) is orbited. See Swiss Patent No. 287,175.

According to experience, the twisting of finer denier threads on double twist twisting devices of customary construction is often connected with difiiculties and in many cases impossible. This shortcoming has to be essentially attributed to the fact that the necessary satisfactory thread balloon development depends, in addition to other factors, upon the weight or titer of the thread and upon the size and shape or length of the feed winding. The inherent readiness of finer threads for satisfactory balloon development decreases, under otherwise equal operating conditions such as rate of revolution of the spindle and draw-off speed, with the reduction of the denier value and/or increase of the length of the feed winding to the point where balloon development fails completely because the balloon collapses readily in the case of slight disturbances, for example, fluctuations of the runoff conditions at the feed Winding, or because the thread is not in a position at all to develop into a freely orbiting balloon. As is well known, the results are in this case reductions of the thread quality through capillary breaks, sling formation or slub formation and the like as well as thread ruptures and production breakdowns.

Exact examinations have shown that the lower limit for the processing of fine denier synthetic polymer threads on 300 mm. long feed windings on double twist twisting 3,391,529 Patented July 9, 1968 devices lies, in terms of satisfactory, freely orbiting balloon development, approximately at 40 denier thread titer. Threads of a smaller denier value than 40 denier can only be processed from shorter and therewith smaller supply windings in order to form satisfactory, freely orbiting balloons. Where a larger distance between the thread guide (e.g., a guide eye or ring) and the reserve ring or disc is necessitated by use of a thread supply winding of approximately 300 mm. and more, the threads tend to form a so-called double balloon, i.e., two balloon segments formed by partial collapse of the orbiting thread. The depth of collapse depends upon the thread titer, and the axial level at which it occurs depends, oddly, upon the outer diameter of the reserve ring or disc. When the denier value is further reduced, the contraction (collapse) becomes by itself so deep that the thread touches the stationary supply winding or the protective casing surrounding it, whereby the balloon collapses and the thread breaks. In this case, the critical contraction zone of the balloon lies-when double twist twisting spindles of customary construction are used-always in the lower balloon half and shifts upwardly in response to reduction of the reserve disc diameter. However, the reduction of the diameter of the thread reserve ring or disc as means for the displacement of the balloon contraction into the upper zone of the supply winding has practical limits. As is well known, a certain minimum diameter of the reserve ring or disc is required so that it is effective, and therefore its diameter cannot be reduced at random or even be kept extremely small. Also, according to experience, thread tension in the balloon is smaller with larger diameters of the reserve element. Hence, increases in thread tension work against substantial reductions of the reserve element diameter.

On the other hand, the industry is interestedin twisting also finer and finest synthetic threads of essentially less than 40 denier thread titer, for example of 15 denier, on the existing double twist twisting machines and in being able to use directly considerably longer and more voluminous spools which are obtained during the thread production in direct manner and in particular in ovoid or elongated, cop shape. This of course avoids the hitherto necessary step of rewinding the thread onto smaller spool units as supply windings in order to obtain knotfree twisted thread lengths of as long a length as possible. Such spools possess often a winding length of 380 to 450 mm. or even more and a winding weight of 3 to 4 kg. and higher. Up to now, the processing of finer and finest man-made threads from such supply windings on double twist twisting machines has not been possible because of the diiiiculties encountered in the balloon formation.

Summary of the invention It is, therefore, the purpose of the invention, to enlarge the application range of the customary or of the existing double twist twisting spindles in such a manner that threads of finer titer from overly long supply rolls can be twisted or processed thereon.

In order to attain this objective, the invention provides that the orbiting thread is supported against the inner side thereof as it runs from the reserve disc to the thread guide during orbiting of the thread at the critical contraction Zone of the thread balloon. The aforesaid support is provided by a support ring rotating concentrically with the spindle. Because of this measure it is possible to brace the thread balloon in the zone of its contraction to prevent is further collapse and to permit it to develop anew. A surprising fact in this case is that, on its further travel from the support ring to the upper thread guide, the thread orbits in an essentially cylindrical course, even when the distance between the support ring and upper thread guide is disproportionately long.

In this manner it is now possible to enlarge the thread balloon height to such an extent that now much longer supply spools can be employed. In contrast to the known state of technology, one can, through the proposed measures, employ such supply windings, in particular in the shape of elongated, cop-type or ovoid spool bodies, and process them on existing double twist twisting devices. The tubes or cops carrying the supply windings may have a length of at least 300 mm., preferably of 380 to 450 mm., and may be made of the finest of synthetic threads (less than 30 denier thread titer, for example of 15 denier) wound at a Winding weight of at least 3 kg.

It is essential in this case that the support ring rotates together with the spindle in order to avoid a harmful cross friction for the thread running over it. Threads of finer titer, in particular, those of delicate material such as polypropylene, are indeed very resistant to a strain in their longitudinal direction, but, on the other hand, they are not able to cope with the strain in cross direction, which would occur in the case of thread running over a stationary support, because of the cross friction acting upon the threads. Such cross friction generates structural defects in the thread or even the melting thereof, the result being thread breakage.

:It was further found that the rotating supporting ring does not have to possess any special width or axial extension. A narrow, circular edge is completely sulficient to prevent deeper contraction of the balloon and to create a new base for the free development of the same between the ring and the thread guide.

The support ring provides on its outer circumference a circular surface which is run over by the thread and is set up at the level of the balloon contraction zone. The support ring rotates together with the spindle and has at least the same outer diameter as the thread run over body, preferably a 10 to 20% larger diameter. The support ring can be rigidly mounted on the run over body of the spindle by length-adustable bars. These bars are adjustable in their length in order to be able to adjust the position of the support ring to best correspond to the respective critical balloon contraction zone.

A special advantage of the invention is that the simple support ring installation can be attached easily to existing double twist twisting machines and that the range of application of these machines can be considerably enlarged through such installation.

the support ring in diametric cross-section, of a preferred embodiment of the invention.

Description of the preferred embodiment The illustrated double twist twisting spindle 1 comprises a whorl or pulley 2 used to drive by a belt (not shown) the spindle about a vertical axis of rotation. Just above the whorl 2 is the customary thread reserve ring or disc 3 into which the thread from thread supply spool 4 is discharged through radial passage 5. The thread travels over the lower surface of the thread run over body 6, which is a ring-shaped member having a rounded, circular peripheral edge 7, and orbits as a thread balloon as it runs to the stationary thread guide 8. The thread run-over body 6 rotates concentrically about the axis of the spindle 1 with the whorl 2. The thread guide 8 is positioned about the thread supply spool 4 and is aligned with the axis of spindle 1. In the illustrated embodiment, the thread guide 8 is a wire loop or pigtail.

The support ring 9 has a narrow, rounded, peripheral edge 10 over which the thread runs when the thread balloon tends to collapse inwardly. The diameter of the edge 10 is at least equal to, and preferably is 10 to 20% larger than, the diameter of the circular edge of run-over body 6. The ring rotates with the spindle 1 about the axis of the latter. It is supportcd by vertical legs 11 on d. the thread run-over body 6. The ring 9 preferably is shiftable axially along the spindle to provide for adjustment of the point of contact between the thread balloon and the ring. For this purpose, the legs 11 may be made from tightly fitted, telescoping sections 12 and 13.

The supply winding 4 comprises an elongated, coptype thread winding on a winding tube 14, and is held stationary on the stationary spool carrier 15 mounted in known manner in the center of the upper part of the run-over body 6. The thread 15 is drawn off its winding or supply spool 4 into the tubular end 16 and emerges from the hollow spindle into thread reserve ring or disc 3 from passage 5. It is drawn by a draw-off or take-oif device (not shown) above the thread guide 8 and orbits in its path of travel in the thread balloon about the supply winding 4. With fine denier thread and the distance between run over member 6 and guide 8, as aforedescribed, the thread balloon collapses inwardly against the support ring 9. The support ring prevents damaging contraction of the balloon and damaging cross friction by rubbing of the collapsed balloon over the stationary spool and forms the base for a new, freely orbiting balloon segment 18 between the ring and the thread guide 8.

The difiiculties which occur in the known art during the processing of specially fine, synthetic threads, using oversized, copshaped supply windings, during the twisting thereof on double twist twisting machines are thread breaks caused by the thread touching the not moving parts of the spindle in the first stage of the development of a balloon, so that a freely orbiting balloon cannot develop. Such difiiculties are, as confirmed by the tests for example with polypropylene threads of 30 denier or perlon threads of 15 denier and supply tubes or cops of 380 to 470 mm. casing length and approximately 3 or 4 kg. winding weight, safely avoided by the invention herein because of the inner support of the thread at an edge of the support ring rotating with the spindle in the critical contraction zone of the balloon. The support ring en-" abling the renewed development of thread balloon segment 18.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. In the process of double twisting of synthetic polymer threads of fine denier with the formation of an obbiting thread balloon about an elongated thread supply winding, the improvement comprising preventing collapse of said thread balloon through touching said thread winding at the critical contraction zone of the thread balloon by causing said thread to run across the outer edge of a rotating member with a circular, narrow, thread-contacting surface positioned at said critical contraction zone.

2. In a process as claimed in claim 1 wherein said thread balloon is orbited about a thread supply winding of at least 300 mm. in length, said thread is less than 30 denier titer, and the weight of the thread wound on said thread supply winding is at least 3 kg.

3. In a double twist twisting apparatus comprising a rotatable spindle having a thread reserve ring and a thread run-over body with a circular edge positioned concentrically on said spindle and rotatable therewith, an elongated thread supply winding immediately thereabove, and passage means extending axially through said winding for feeding thread from said winding to said thread reserve ring and then over said run-over body to a thread guide above said supply winding in the form of an orbiting thread balloon, the improvement comprising a thread support ring mounted concentrically on said spindle about said winding and rotatable with said spindle for preventing collapse of the orbiting thread balloon through touching said thread winding, the diameter of the outer edge of said thread support ring being at least equal to the diameter of said circular edge of said thread run-over body.

4. In a double twist twisting apparatus as claimed in claim 3, wherein said diameter of said outer edge of said thread support ring is about 10-20% larger than the diameter of said circular edge of said thread run-over body.

5. In a double twist twisting apparatus as claimed in claim 3, and means connecting said thread support ring and said thread run-over body and supporting said support ring for rotation with said run-over body.

6. In a double twist twisting apparatus as claimed in claim 5, wherein said last-mentioned means comprises length-adjustable support members extending between said thread support ring and said run-over body.

7. In a double twist twisting apparatus as claimed in claim 3, and said thread support ring having an outward bent narrow, rounded edge.

References Cited 5 UNITED STATES PATENTS 2,638,732 5/1953 Sabaton 57-58.83 2,692,471 10/ 1954 Landolt 5758.83 XR 2,734,333 2/1956 Griset et a1. 5758.86 XR 0 3,276,197 10/1966 Franzen 57-58.83

FOREIGN PATENTS 1,062,705 4/ 1954 France. 1,109,507 1/1956 France.

602,419 8/ 1934 Germany. 682,391 11/1952 Great Britain. 726,944 3/ 1955 Great Britain.

FRANK. I. COHEN, Primary Examiner.

20 DONALD WATKINS, Assistant Examiner. 

